1. Field of the Invention
The present invention relates to an ink jet printer, and, more particularly, to a method for increasing the waste ink storage capacity in an ink jet printer by utilizing multiple ink spit areas along the carrier path.
2. Description of the Related Art
A typical ink jet printer includes a reciprocating carriage, also known as a carrier, carrying at least one ink jet printhead. The printhead includes a nozzle plate having a plurality of ink jet nozzles. Associated with each nozzle is an actuator, such as an electric heater or a piezoelectric device, that when electrically energized causes ink to be ejected from the respective ink jet nozzle. As a sheet of print media is transported in an indexed manner under the printhead, the printhead is scanned in a reciprocating manner across the width of an image area on the sheet of print media. At least a portion of the carrier scan path of the reciprocating printhead defines a print zone. A platen is provided opposite to the printhead for contacting the non-printed side of the print media and, in part, defines the distance between the printhead and the sheet of print media. The actuators associated with the plurality of ink jet nozzles are selectively energized to form an image on the sheet of print media in the image area.
Ink jet printers require maintenance operations to keep the nozzles of the print cartridge operating properly. A maintenance station for performing the maintenance operations typically include at least one printhead wiper, and one cup-shaped printhead cap for each printhead. Such maintenance operations typically include the steps of wiping the nozzle area of the print cartridge, firing the nozzles at prescribed intervals to purge the nozzles (spitting), and capping the cartridge during idle periods to prevent the jetted ink which remains on the nozzle plate from drying and clogging one or more of the nozzles of the nozzle plate.
Briefly, a wiping sequence commences with the printhead over the media feed path and the top of the wiper below the printhead scan path. The wiper is raised until it extends into the path of the printhead surface containing the nozzles, and the printhead is moved to engage the wiper. Thus, accumulated ink and other foreign matter are wiped from the printhead as the printhead moves past the wiper. Typically, the spitting operation occurs at a location in the maintenance station, such as a waste ink spittoon provided on a maintenance sled. During the capping operation, the printhead is moved over the printhead cap and the cap is raised into contact with the printhead in an attempt to form an air tight seal around the region in which the nozzles are located.
During the period that the printhead has been capped, a limited amount of evaporation occurs around the printhead. This evaporation raises the humidity levels inside the cap, and eventually, the evaporation subsides. In order to prepare the printhead after a dormant period, a wiping and spitting operation is performed prior to actual printing. Also, a spitting operation is invoked if during printing a printhead nozzle has remained unfired for a predetermined period of time. In addition, after the printhead has been in use for a predetermined period of time, the wiping and spitting sequence of operations may be performed.
Over a period of time, as a result of the spitting operation the solids in the waste ink accumulate in the maintenance station. Such solids are present, for example, in pigment based monochrome inks. The resulting waste ink buildup can affect the operation of the maintenance assembly. Also, if the waste ink accumulates to a mound height that can contact the printhead, then the printhead can become contaminated by contact with the accumulated waste ink. The vertical growth of the monochrome waste ink accumulation is a function of the spit maintenance duty cycle, i.e., for a given number of monochrome printhead ink spit maintenance cycles, smaller duty cycles tend to build vertical mounds of waste ink faster than longer duty cycles. Many color inks are dye based, and therefore do not include the solids that contribute to vertical growth waste ink buildup.
One previous attempt to accommodate the waste ink ejected during a spitting operation that reduces the waste ink accumulation at the maintenance station is to perform a portion of the spitting operations on-page on a printed sheet at locations where the ejected ink would not adversely affect the print quality of the printed sheet. Such an approach, however, requires a relatively complicated control algorithm and requires exact placement of the ejected ink so as to avoid the appearance of printing imperfections on the printed sheet.
What is needed in the art is an effective method for increasing the waste ink collection capacity of an ink jet printer that does not require placement of ink droplets on a printed page or the inclusion of additional complicated maintenance hardware.
The present invention provides an effective method for increasing the waste ink collection capacity of an ink jet printer.
The invention provides, in one form thereof, a method including the steps of providing a printer frame including a first frame portion and a second frame portion; providing a platen extending between the first frame portion and the second frame portion; providing a maintenance station coupled to the first frame portion; providing a printhead carrier for carrying a first printhead and a second printhead, and adapted for reciprocating movement along a carrier path, the carrier path extending over the first frame portion and the platen; defining a first ink spit area located at the maintenance station; defining a second ink spit area located at the platen; and selectively controlling an operation of the first printhead during spitting operations to eject a first ink in the first ink spit area and selectively controlling an operation of the second printhead during spitting operations to eject a second ink in the second ink spit area.
In another form, the invention provides a method including the steps of defining a first ink spit area located outside a print zone of the printer; defining a second ink spit area located in the print zone of the printer; defining a third ink spit area located outside the print zone, the print zone being located between the first ink spit area and the third ink spit area; and selectively controlling an operation of a selected one of a plurality of printheads during spitting operations to eject ink in a selected one of the first ink spit area, the second ink spit area and the third ink spit area.
In still another form thereof, the invention provides a method including the steps of providing a printer frame including a first frame portion and a second frame portion; providing a platen extending between the first frame portion and the second frame portion; providing a maintenance station coupled to the first frame portion; providing a printhead carrier for carrying a printhead, and adapted for reciprocating movement along a carrier path, the carrier path extending over the first frame portion, the platen and the second frame portion; defining an ink spit area located at one of the platen and the second frame portion; and selectively controlling an operation of the printhead during spitting operations to eject a pigment based ink in said ink spit area.
An advantage of the present invention is that the effective waste ink collection capacity of an ink jet printer is increased without the inclusion of additional complex maintenance hardware.
Another advantage of the present invention is that the effective waste ink collection capacity of an ink jet printer is increased without increasing the printer size, such as for example, without increasing the printer height.
Another advantage of the present invention is that the effective waste ink collection capacity of an ink jet printer is increased without requiring placement of ink droplets generated during a spit operation on a printed page.